Portsmouth Earthworks

Portsmouth Earthworks is an ancient complex of earthen mounds extending roughly 20 miles along the Ohio River valley with circular enclosures and horseshoe-shaped structures. The site is divided into distinct groups, each displaying different geometric patterns and arrangement of mounds.

The complex was constructed between approximately 100 BCE and 500 CE by the Adena and Ohio Hopewell cultures. It was built at the confluence of the Scioto and Ohio Rivers, where these peoples created large ceremonial landscapes.

These earthworks served as gathering places for ceremonies and spiritual practices among ancient peoples in the region. Visitors can observe how the remaining structures shaped the landscape and demonstrate the engineering knowledge of those who built them.

Mound Park is the only public access point where visitors can view a preserved horseshoe-shaped mound from the original complex. The site is most accessible and the earthwork shapes are clearest during dry weather conditions.

Research suggests the mounds of Group B may form a large female effigy pattern spanning several miles across the landscape. This unusual geometric design might connect to Native American origin stories and sacred geography.

Location: Scioto County

GPS coordinates: 38.72160,-83.02305

Latest update: December 9, 2025 18:44